Research on fatigue behavior and residual stress of large-scale cruciform welding joint with groove

• The fatigue behavior of the large-scale cruciform welding joint with groove was studied.
• The longitudinal residual stress of the large-scale cruciform welding joint was tested by contour method.
• The fatigue fracture mechanism of the large-scale cruciform welding joint with groove was analyzed.

Fatigue fracture behavior of the 30 mm thick Q460C-Z steel cruciform welded joint with groove was investigated. The fatigue test results indicated that fatigue strength of 30 mm thick Q460C-Z steel cruciform welded joint with groove can reach fatigue level of 80 MPa (FAT80). Fatigue crack source of the failure specimen initiated from weld toe. Meanwhile, the microcrack was also found in the fusion zones of the fatigue failure specimen, which was caused by weld quality and weld metal integrity resulting from the multi-pass welds. Two-dimensional map of the longitudinal residual stress of 30 mm thick Q460C-Z steel cruciform welded joint with groove was obtained by using the contour method. The stress nephogram of Two-dimensional map indicated that longitudinal residual stress in the welding center is the largest.